CN114667384A - Switchable and addressable switch assembly for wellbore operations - Google Patents

Abstract

A switchable and addressable switch assembly (632) comprising: an interface (I/O) configured to connect (800) to a controller (206) along a telemetry system (205); and a processor (P)_A) Connected to the interface (I/O). The processor is configured to: receiving (802) a command from the controller (206) along the telemetry system (205) to change a first value of a mode state variable to a desired second value, wherein the first value is associated with a first operating mode of the switch assembly (632) and the second mode is associated with a second operating mode different from the first operating mode; changing a first value to a second value within the switching assembly; and in the switch assembly (632) Storing (896) the second value of the mode state variable in a non-volatile memory (238).

Description

Switchable and addressable switch assembly for wellbore operations

Technical Field

Embodiments of the subject matter disclosed herein relate generally to downhole tools for oil and gas operations, and more particularly, to gun strings having one or more addressable switch assemblies that may be switched in firmware to perform an action by one of a plurality of operating modes.

Background

After the well 100 has been drilled to a desired depth H relative to the surface 110 and the housing 110 protecting the wellbore 104 has been installed and cemented in place as shown in fig. 1, it is time to connect the wellbore 104 to the subterranean formation 106 to extract oil and/or gas.

The process of connecting a wellbore to a subterranean formation can include the steps of: (1) a plug 112 with a through hole 114 (called a frac plug) is placed over the stimulation-only stage 116, (2) the plug is closed, and (3) a new stage 118 is perforated over the plug 112.

As shown in fig. 1, the conventional gun string 120 includes a plurality of carriers 126 connected to one another by corresponding joints 128. Each joint 128 may include an initiator 130 and a corresponding switch 132. The detonator 130 is not connected to a through wire (a lead wire that extends from the surface to the last gun and sends an activation command to the charge of the gun) until the corresponding switch 132 is activated. The corresponding switch 132 is actuated by the firing of the downstream gun. When this occurs, the detonator 130 becomes connected to the through-line and the upstream gun is activated when a command from the surface activates the detonator 130.

For a conventional perforating gun string 120, the carrier 126 is first loaded with charges and corresponding detonator cords to form a plurality of gun assemblies. The gun assemblies are constructed by connecting the loaded carriers 126 to the corresponding adapters 128 and then one gun assembly at a time. These connections include a switch 132 having air-tight barrier capabilities. Once the nosepiece is assembled to the gun assembly, the leadwire and detonating cord are pulled into the nosepiece through the port, allowing installation of the detonator, corresponding switch and connection of the leadwire. Those skilled in the art will appreciate that such assembly operations have their own risks (i.e., miswiring) that may render one or more of the switches and corresponding detonators unusable.

After the conventional gun assemblies have been placed together to form a gun string, none of the detonators are electrically connected to a through lead or through line running through the gun string. This is because there is a pressure actuated Single Pole Double Throw (SPDT) switch between each gun assembly. Normally closed contacts on these switches connect the through wires from the gun assembly to the gun assembly. Once the switch has been activated by the explosion of the lower gun assembly (when the gun is fired), the switch changes its state, connecting the feedthrough from above to one of the conductors of the detonator. The other conducting wire of the detonator is always grounded through a lead wire.

In this configuration, it is not possible to select which of the plurality of switches is to be activated after assembly. Upon sending a firing command from the controller 124, the most distal switch is activated. The explosion from the corresponding gun assembly then activates the next switch and so on. However, new technologies are using addressable switches (i.e., switches with processors with ID addresses), and the surface controller 124 is configured to send the target command to the desired addressable switch based on the unique ID of each switch.

However, these addressable switches need to be configured prior to deployment into the well, to act as conventional switches, or to act as fast firing switches, etc. Thus, based on the needs of the operator operating the well, the manufacturer of the addressable switch programs it in hardware to perform actions as needed. This programming step involves hard coding different firmware onto the switch's local processor. Once the switch has been packaged and ready for delivery, it is impractical to reprogram the processor, as this requires a significant amount of skill and time to complete the operation, and the packaging will prevent access to the connection points required for programming. Thus, currently, well operators need to exercise a significant level of forecasting to know how many switches of each type are to be ordered from the manufacturer. This is problematic for well operators, as it is almost impossible to know in advance what type and how many switches a given well will require.

Accordingly, there is a need to provide a downhole system that overcomes the above problems and provides the operator of the well with the ability to select any mode of operation associated with the addressable switch after the gun string has been delivered to the well.

Disclosure of Invention

According to an embodiment, there is a switchable and addressable switch assembly that is part of a chain of switch assemblies in a gun string. The switch assembly includes: an interface configured to connect to a controller along a telemetry system; and a processor connected to the interface. The processor is configured to: receiving a command from the controller along the telemetry system to change a first value of a mode state variable to a desired second value, wherein the first value is associated with a first operating mode of the switch assembly and the second mode is associated with a second operating mode different from the first operating mode; changing the first value to the second value; and storing the second value of the mode state variable in a non-volatile memory.

According to another embodiment, there is a method for actuating a switch assembly that is part of a gun string. The method comprises the following steps: receiving power at the switch assembly from a surface controller; checking, at the switch component, a value of a mode state variable stored in a non-volatile memory; and activating the switch assembly according to one of a plurality of operating modes based on the value of the mode state variable. Each of the plurality of operating modes is different from the other of the plurality of operating modes.

According to yet another embodiment, there is a switchable and addressable switch assembly configured to be connected to a gun assembly in a gun string for energizing the gun assembly. The switch assembly includes: processor (P)_A) Configured to check a value of a mode state variable; a memory configured to store (1) the value of the mode state variable and to store (2) a unique digital address that makes the switch assembly addressable; a pass-through switch configured to allow a signal from the surface controller to pass to a next switch assembly; a detonator switch configured to complete a circuit to a detonator to detonate the detonator; and a transceiver configured to communicate directly with the next switching component. The value of the mode state variable is associated with a plurality of operating modes. The switch assembly is switched from one operating mode to another operating mode by changing the value of the mode state variable.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate one or more embodiments and, together with the description, explain these embodiments. In the drawings:

figure 1 shows a well and associated equipment for well completion operations;

fig. 2 shows a chain of addressable switch assemblies and associated gun assemblies;

fig. 3A and 3B illustrate possible configurations of addressable switch assemblies;

4A-4C are flow diagrams of methods for selecting an addressable switch assembly and actuating an associated detonator;

FIG. 5 illustrates in more detail the steps of selecting the operating mode of the switchable and addressable switching assembly;

FIG. 6 illustrates a configuration of a switchable and addressable switch assembly;

FIG. 7 shows a chain of switchable and addressable switch assemblies distributed in a gun string;

FIG. 8 is a flow chart of a method for configuring the operating mode of one or more switchable and addressable switch assemblies; and

fig. 9 is a flow chart of a method for operating one or more switchable and addressable switch assemblies.

Detailed Description

The following description of the embodiments refers to the accompanying drawings. The same reference numbers in different drawings identify the same or similar elements. The following detailed description does not limit the invention. Rather, the scope of the invention is defined by the appended claims. For simplicity, the following embodiments are discussed with respect to a switchable and addressable switch assembly that switches from one operating mode to another operating mode in firmware rather than in hardware using a telemetry system of a gun string. The embodiments discussed herein are applicable to switching a switchable and addressable switch between two or more modes of operation.

Reference throughout the specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the subject matter disclosed. Thus, the appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

According to the embodiment shown in fig. 2 (which corresponds to fig. 2 of international patent application PCT/US2019/036538, which is incorporated herein by reference and assigned to the assignee of the present application), the gun string 200 includes a plurality of gun assemblies 240 (shown as elements 240A through 240M, where M may take any number) connected to one another by corresponding joints 210 (numbered 210A through 210M in the figures). In one application, the adapter is not used to connect gun assemblies to each other. If a sub is not used, the element 210 may be an initiator module that attaches to a corresponding gun assembly and carries a switch assembly. Although fig. 2 shows the element 210 as being physically visible from outside the gun string, in one application it is possible to have the sub or initiator sub 210 fully within one or both adjacent gun assemblies so that the element 210 is not visible from outside when the gun string is fully assembled. Note that each gun assembly (except for the uppermost gun assembly 240A and the lowermost gun assembly 240M) is sandwiched by two nipples or two initiator modules. The upper gun assembly 240A is considered the gun assembly that is first connected to the cable (not shown in fig. 2), while the lower gun assembly 240M is considered the gun furthest from the cable (i.e., the gun assembly connected to the setting tool 202 (if present)).

A plurality of switch assemblies 232A-232M and a plurality of detonators 230A-230M are distributed along the gun string 200. In this embodiment, each sub or initiator assembly 210 includes a corresponding switch assembly and initiator (i.e., sub 210A includes switch assembly 232A and initiator 230A). The same is true for all other joints. In one application, the initiator may be located outside the joint. Detonator 230A is electrically connected to switch assembly 232A and ballistically connected to corresponding gun assembly 240A. The same is true for other gun assemblies, detonators and switch assemblies.

The switch assembly 232A (hereinafter, reference is made to a particular switch assembly, but it is to be understood that this description is valid for any switch assembly in the chain of switch assemblies shown in fig. 2) includes a processor P_A(e.g., an application specific integrated circuit or a field programmable gate array or equivalent semiconductor device) that is electrically connected to the two switches. The first switch is a through-line switch 234A, which may be implemented in software (e.g., firmware) or hardware or a combination of both. The through line switch 234A is connected to the through line 204. The through line switch 234A is in this embodiment implemented by the processor P_AAnd (5) controlling. The through-wires 204 may extend from the surface controller 206 along the cable. The portion of the through line 204 that enters the switch assembly 232A is referred to herein as the input through line 204A-i, and the portion that exits the switch assembly 232A is referred to as the output through line 204A-o. When the through-line switch 234A is open, power or other signals sent downhole from the controller 206 cannot pass through the switch assembly 232A to the next switch assembly 232B. By default, all through line switches 234A through 234M are open.

In this embodiment, the controller 206 may not only send commands, but may also apply various voltages to the through line 204. This embodiment shows only a single line (through line 204) extending from the controller 206 to the lower through line switch 234M. However, those skilled in the art will appreciate that more than one lead may extend from the controller 206 to the various switch assemblies. For example, the ground line may extend parallel to the through line. In this embodiment, the ground wire duties are performed by the housing of the gun assembly.

The switch assembly 232A also includes a detonator switch 236A, which is also processed by the processor P_AAnd (5) controlling. The detonator switch 236A can be implemented similar to the through-wire switch 234A. The detonator switch 236A is open by default, and thus, the control signal cannot be from the controller 206 or the processor P_ATo the corresponding detonator 230A. The switch assembly 232A may further include a memory 238A (e.g., an EPROM memory) for storing digital addresses and/or other information.

The numeric address of the switch assembly may be assigned in various ways. For example, it is possible that all switch assemblies have pre-assigned addresses. In one application, it is possible that the switch assembly has a random address (i.e., an address assigned by the manufacturer of the memory or an address that happens to be made when the memory is manufactured). In another embodiment, it is possible that the predetermined set of addresses is assigned by the manufacturer of the gun string.

The lower switch assembly 234M differs from the other switch assemblies in the following sense: in addition to the input through line 204M-i and the detonator 230M, the switch assembly 234M is also connected to the setting tool detonator 250. The setting tool detonator 250 may have the same configuration as the detonator 230M, but it is used to actuate the setting tool 202. The setting tool 202 is used to set the plug 112 (see fig. 1). Therefore, the lower switch assembly needs to distinguish between the following two modes: (1) firing the gun detonator 230M or (2) firing the setting tool 202. Methods for achieving these results are discussed later.

The configuration of the addressable switching assembly 232 (which may be any of the switching assemblies 232A-232M discussed with respect to fig. 2) is shown in more detail in fig. 3A and 3B. The addressable switch assembly 232 includes a through wire switch 234 and a detonator switch 236. As described above, the two switches may be implemented in hardware (e.g., having a semiconductor device that may include one or more diodes and/or transistors) or in software or both. In this embodiment, it is assumed that the two switches are implemented in software (i.e., the processor P)_AIn (1). In this case, the two switches 234 and 236 in fig. 3A and 3B are logic blocks that describe the functions performed by these switches and also their connections to other elements. This means that these logical blocks are physically implemented in the processor P_AIn (1).

Processor P_AMay further comprise a logic voltage measurement block V_MWhich is configured to measure the voltage present in the through line 204 (or more specifically, the input through line 204-i). Further, the processor may include an interface (e.g., a logical or physical block I/O) that may exchange various input and output commands with the controller 206 via the through line 204. The logic block I/O may also be connected to the voltage measurement block V_MA communication is made for receiving the measured voltage V and providing the value to a computation core CC of the processor for various computations. Processor P_AIs connected to the memory 238 via a bus 239. The compute core CC is capable of storing and/or retrieving various data and performing various computations from the memory 238. In one embodiment, memory 238 is an erasable programmable read-only memory (EPROM) (i.e., a non-volatile memory), which is a type of memory that retains its data when its power is turned off. This type of memory has the advantage of retaining the address and/or mode state variables associated with the switch assembly when power is not being supplied. With respect to power, note that in this embodiment, the switch assembly receives its power along pass-through line 204 (i.e., there is no local power source in the switch assembly or junction).

Processor P_AA communication unit CU may also be included, which is configured to exchange data with the controller 206. As will be discussed later, various commands may be sent by the controller 206 to a given switch assembly. The communication unit CU intercepts those commands (sent along the through line 204) and determines, in cooperation with the computational core CC, whether the command is addressed to a particular switching component. The communication unit CU is further configured to: upon power-up operation of the switch assembly, the address of the switch assembly (the digital address of the switch assembly, which is stored in the memory 238) is sent to the controller 206. The communication unit CU may be configured to use any known communication protocol. The communication unit CU may be implemented in software as a processor P_AAs shown in fig. 3A. However, the communication unit may also be implemented as dedicated hardware or as a combination of hardware and software. For example, fig. 3B shows that the communication unit CU is implemented as a receiver R and a transmitter T. Fig. 3B also shows a local controller 206'.

Processor P_AOne or more timers may also be included. Fig. 3A shows a first timer 246A and a second timer 246B. These timers may be implemented in software, and thus the blocks labeled 246A and 246B in fig. 3A describe the logical blocks associated with these timers. These timers may be implemented in the controller 206' in the embodiment shown in fig. 3B. However, in one embodiment, these timers may be implemented as dedicated hardware, with or without appropriate software. Although fig. 3A shows two timers, those skilled in the art will appreciate from this description that only one timer or more than two timers may be used. The timer is configured to count a given time interval. For example, the first timer 246A may count down from 20 seconds, while the second timer 246B may count down from 1 second. Other values may be used. Once a given time interval has elapsed, the timer sends a message to the processor indicating this fact. As will be discussed later, these timers may be used to implement a safe procedure with respect to firing of the detonator.

Fig. 3A further shows two leads (fire wires) 236A and 236B connecting the detonator switch 236 to the detonator 230. The embodiment of fig. 3B uses only a single lead 236A for connecting the detonator switch 236 to the detonator 230. The two leads in fig. 3A are connected to an initiator 230 that is not part of a switch assembly 232. However, it will be appreciated by those skilled in the art that the detonator may be made part of the switch assembly. The elements discussed above with respect to the switch assembly 232 are located inside the housing 242. The housing may be made of metal (e.g., aluminum) or a composite material. In one embodiment, the switch assembly is located inside the initiator block 210 that is configured to also carry an initiator. The entire switch assembly may be distributed on a printed circuit board 244, as schematically illustrated in fig. 3A.

The embodiment of fig. 3B shows that two lines 204 and 204' may enter the switching assembly, where one line has a positive voltage and the other line has a negative voltage. The switching assembly may have its own power supply 205 that supplies a DC voltage (e.g., 5V) to the controller 206'. The embodiment shown in fig. 3B also includes a fail-safe mechanism 233 for a through-line switch 234 and a fail-safe mechanism 235 for a detonator switch 236. The switch load detection unit 207 detects whether there is an electrical load on the outputs of the switches 234 and 236. The switch load detection unit 207 reports the load status to the controller 206 'and this information is sent to the surface controller 206 and/or used by the downhole controller 206' in its decision tree.

The arrangement shown in fig. 3A or 3B can be used for all switch assemblies shown in fig. 2, for switch assemblies connected to a single detonator, but also for lower switch assemblies connected to a gun detonator and to a detonator of a setting tool. Previously, setting tools required a separate and uniquely addressable switch for energizing the setting tool detonator. The switch assembly shown in fig. 3A and 3B eliminates the need for setting the tool switch because the address of the bottom gun addressable switch assembly allows the switch assembly to perform two functions: a firing voltage is applied to the detonator of the setting tool and thereafter the same or a different firing voltage is applied to the detonator of the bottom gun assembly.

Further, the switch assembly 232 can now be remotely programmed such that it performs an action by default in a first mode of operation (e.g., as a standard addressable switch), or in a second mode of operation (e.g., as a fast-firing addressable switch), or in a third mode of operation (e.g., as a set/fire addressable switch), or in a fourth mode (e.g., as a fast-firing set/fire switch). All of these modes are discussed in more detail later. While this embodiment illustrates the ability of the same switch assembly 232 to be programmed to perform actions according to four different operating modes, those skilled in the art will appreciate that the switch assembly may be programmed to perform actions according to more or fewer operating modes. To switch the switch assembly 232 from one mode of operation to another of the above-described modes of operation, the existing telemetry system of the gun string may be used by the controller 206 and one or more instructions may be sent to the switch assembly to change the communication with the processor P_AThe value of the mode state variable in the associated memory 238.

In this manner, an operator of the gun string may use a single switch assembly part number for any well, and if it is desired to have the switch assembly operate in a given mode of operation, a given bit of information in the memory 238 of the switch assembly 232 may be changed to the desired mode of operation just prior to deployment of the gun string into the well. Although in this embodiment the mode of operation of the switch assembly 232 is selected prior to deployment of the gun string into the well, the same operation may be performed after the gun string has been deployed into the well. In one application, all of the switch assemblies 232 are modified to operate according to the same selected operating mode. This means that if the switch assembly is transported to an operator of the well to operate in a given mode of operation, the operator can change all switch assemblies to operate in another mode of operation. However, in one embodiment, it is possible to select only a subset of the switching components using their numerical addresses and to change all of these switching components from a given operating mode to another operating mode, and leave all other switching components unmodified. Details of how the addressable switching assemblies are converted from one operating mode to another and how it is determined in which operating mode a given switching assembly is operating are discussed later.

The digitally switchable and addressable switch assembly 232 of fig. 3A or 3B is programmed to communicate with a surface logging and/or perforating system (e.g., controller 206), thus providing improved safety and perforation reliability of individual gun control from the surface. The configuration shown in fig. 2, which includes multiple addressable switch assemblies, has the ability to fire a single gun assembly, typically from the bottom of the gun string. It also provides for skipping any one or more gun assemblies in the string that may be defective, thereby continuing the perforating process that fires a single gun assembly with any remaining gun assemblies in the string.

The switch assembly 232 may be designed to provide a precise form of replacement for EB-type switches currently used in the industry. The electronic circuit board 244 of the switch assembly 232 may be enclosed within the metal housing 242 by a thermally conductive, electrically insulating epoxy that also provides both electrical and mechanical shock resistance. The switch assembly is constructed without moving parts so that it is shock resistant to withstand the explosion of the perforating gun assembly and well pressures downhole.

In one embodiment, the processor and/or memory of each switch assembly is pre-programmed with a unique numerical address that can be dynamically changed in the field. Each switch assembly is located within a joint connected to the gun assembly to enable firing of that particular gun assembly while maintaining pressure containment for intrinsically safe arming and firing of a single particular gun assembly. As noted above, the gun string is then made up of a plurality of pre-assembled and tested gun assemblies typically connected end-to-end and lowered to the bottom of the production well. However, as noted above, if splices are not used in a particular gun string, the switch assembly is located in other components of the gun string.

Starting with the setting tool, the gun string, which sets the drillable bridge plug. The plug seal is hydraulically tested before the perforating operation begins, and thereafter the bottom gun assembly in the string is fired, and then a plurality of gun assemblies are fired at predetermined points along the path of the borehole. As each gun assembly is fired, the pass-through line and electronics associated with the corresponding switchable and addressable switch assembly 232 are damaged/disabled by the pressure wave generated by the charge of the gun assembly. Thus, the switchable and addressable switch assembly cannot be reused for a second shot. However, the mechanical housing 242 of the switch assembly 232 is configured to maintain the pressure integrity of the adjoining gun assembly and the electronic circuit is reset to prevent the application of a voltage to accidentally fire the next gun assembly.

Each switch assembly may be configured in the processor P_AInternal software to provide the ability to fire individual gun assemblies or to serve as a bottom gun/setting tool switch at the site at the discretion of the operator. Furthermore, each switch assembly has the ability to adjust a given byte of its memory for indicating which mode of operation to employ. The firing capability of the lower switch assembly is selected at the final assembly of the gun string by changing the address to, for example, a predetermined value to achieve this function.

Selection of a given switch assembly and various operating and/or operational modes associated with firing of the gun assembly will now be discussed with respect to fig. 4A-4C. It is assumed that the switch assembly has been provided in the corresponding sub and the sub has been connected to the corresponding gun assembly, thereby assembling the entire gun string. Further, it is assumed that all switch assemblies have been programmed by the manufacturer as standard addressable switch assemblies (i.e., operated in a standard mode of operation). Power is applied to the gun string in step 400 from the controller 206 (see fig. 2) through the cable (which includes a straight line), either before the gun string is lowered into the well or after the gun string has been deployed inside the well. At this point, as shown in fig. 2, all of the through-line switches of the switch assembly are open, meaning that power is received only by the upper switch assembly 232A and not by the other switch assemblies.

After receiving power in step 400, the first switch assembly 232A sends its digital address up to the controller 206 in step 402. As described above, the numeric address may be pre-assigned by the operator of the gun string prior to assembly of the gun string, may be pre-assigned by the manufacturer of the gun string, or may be a random address generated when the memory 238 is manufactured. In one embodiment, the numerical address of the entire switch assembly may even be an incomplete address. After sending its digital address to the surface controller 206, the switch assembly waits for a command from the controller 206 in step 404.

The controller 206, upon receiving the numerical address of the first switch assembly in the chain of switch assemblies, stores the address in the associated memory and maps the first switch assembly in the chain with the numerical address. The mapping may be recorded in a table maintained by the controller. As each switch assembly powers up, the table will also include the numerical addresses of all switch assemblies in the chain.

After all the through-line switches are on and the controller is able to communicate with each of them, further commands may be sent from the controller. As the command from the controller 206 is sent along the through line 204, each switch assembly intercepts the command and verifies in step 408 whether the address carried by the command matches the address of the switch assembly. If the result of this step is "NO", the process proceeds to step 410, which returns the process to step 406: waiting for a command. However, if the result of step 408 is "yes" (i.e., the command sent by the controller 206 is intended for a given switch assembly), then the process proceeds to step 412, where it is determined whether the command is valid for the given switch assembly. For example, assume that the command includes the correct numerical address of the upper switch assembly 232A, but instructs it to fire the detonator of the setting tool. As previously described, the setting tool is controlled by the lower switch assembly 232M rather than the upper switch assembly 232A. In this case, step 412 determines that the command, although addressed to the correct switching element 232A, is invalid for that switching element. Thus, the process returns to step 406 for waiting for another command.

However, if the received command has the correct numerical address and is a valid command for switch assembly 232A, the process proceeds to step 414. In step 414, the processor of the switch assembly determines whether the command relates to: (1) changing the address of the switch component, and/or (2) changing the value of a mode state variable at a given location in the memory 238. In one application, the given location is in a non-volatile portion of the memory 238. The mode state variables may take any number of desired values. For example, in one application, the mode state variable may take two values: 0 or 1, where 0 indicates a "standard addressable switch" state and 1 indicates "fast fire addressable switch", or vice versa. However, in another application, it is possible to implement more modes of operation, in which case the mode state variable may take 4 or more values.

Thus, in block 414, the switching element 232 determines whether its numerical address needs to be changed, or its operating mode needs to be changed, or both parameters need to be changed, or neither needs to be changed. If any of these parameters need to be changed, the process proceeds to step 416, during which the original numerical address of the switch assembly is replaced with a new numerical address selected by the operator of the chain, and/or the mode state variable is changed from one value to another (i.e., the switch assembly is changed from one operating mode to another).

In other words, according to this step, the operator can not only dynamically assign new addresses to some or all of the switch assemblies of the gun string (due to the switch assembly addressable nature), but can also change the operating mode of some or all of the switch assemblies (due to convertibility) as the field conditions of the well require. If a new address for the switch component and/or a new value for the mode state variable has been assigned in step 416, the new address and/or new value is written to the non-volatile portion of memory 238, and then the process returns to wait step 406 via step 410. Alternatively, if the original address of the switch assembly is incomplete, the operator can complete the address using the above process.

If the command from the controller 206 is not associated with assigning a new digital address and/or a new value for a mode state variable, the processor P_AIn step 418 it is checked whether the command relates to a "pass-through" command. The pass-through command is designed to turn on the through-line switch 234A so that power can be supplied to the next switch assembly 232B. If this is the case, then in step 420, the processor P_ASwitch 234A is turned on and the process returns to wait step 406.

If the command received in step 418 is not a pass-through command, the process proceeds to step 422, where it is determined whether the command sent by the controller 206 is a "fire" type command. The firing type command instructs the switch assembly to turn on the detonator switch for firing the corresponding detonator. As previously mentioned, the switch assembly may be configured to fire the detonator in a standard mode or a fast fire mode or other modes as will be discussed later. At this step, the processor of the switch assembly checks the value of the mode state variable and determines whether the switch assembly should be initialized for either the standard mode of operation or the fast fire mode of operation. Note that while the switch assembly may be initialized for other modes, only these two modes of operation are discussed herein for simplicity.

Here, FIG. 5 illustrates step 422 in more detail, and illustrates that upon receiving a command from the controller 206, the processor of the switch assembly 232 checks the mode state variables stored in the non-volatile memory in step 500 and determines that the switch assembly should be initialized for the standard operating mode 510 (which is detailed in steps 424 through 442) or that the switch assembly should be initialized for the fast fire operating mode in step 520 (which is discussed later with respect to FIG. 7). Accordingly, steps 510 and 520 prepare the switch assembly according to the desired operating mode. In one application, it is possible to perform step 500 directly after applying power in step 400 in fig. 4A. For this purpose, steps 500 and 520 are shown with dashed lines after step 400. Those skilled in the art will appreciate that steps 500, 510 and 520 may be performed virtually anywhere along the chain of steps shown in fig. 4A prior to step 422.

If the command in step 422 is a fire command and the value of the mode state variable corresponds to the standard mode of operation, the process proceeds to step 424, at which point the first timer 246A is started. Note that step 422 has initialized the switching component to perform an action in either the standard fire mode or the fast fire mode or other modes discussed later. The first timer 246A may be programmed to count down a first time interval (e.g., a 20 second period). Other time periods may be used. The processor checks in step 426 if a time period has elapsed. If the answer is "yes," the process stops the first timer (and other timers (if they have already started)) in step 428 and returns to wait step 406.

A second timer 246B may also be started in step 424. Starting the second timer is optional. If the second timer is present and started, it counts down a second time interval that is shorter than the first time interval of the first timer. In one application, the second time interval is approximately 1 second. When the processor determines in step 430 that the second time interval has elapsed, the processor sends the status of the switch assembly (e.g., whether the switch is on or off, whether the voltage has been measured, the value of the mode state variable, etc.) back to the controller 206 in step 432. Further, in the same step 432, the second timer is reset to count down the second time interval again.

The use of these two counters will now be explained. Returning to step 422, assume that a fire command has been sent from controller 206 to switch assembly 232A. To actually fire the detonator associated with the switch assembly, it is not sufficient to send only the firing command (first condition) because the command may be sent incorrectly. Thus, in order to actuate the detonator, a second condition needs to occur. The second condition is: a parameter (e.g., voltage) characterizing the through line 204 is detected and a determination is made as to whether the value of the parameter is greater than a given threshold in step 434. For example, the threshold voltage may be 140V. Other values may be used. Note that the voltage in the through line during normal operation is much less than the threshold voltage (e.g., about 30 to 40V). Those skilled in the art will appreciate that other parameters (e.g., a given frequency) than voltage may be used.

Here, the controller 206 with the capability to change the value of the mode state variable in the non-volatile portion of the memory of each switch assembly is configured to: when interacting with the switching assembly for setting the value of its mode state variable, operation is performed in a low voltage mode. This is to prevent accidental firing of the detonator. Thus, in this mode, the controller 206 is configured to generate a signal having electrical power at a percentage of the minimum firing current required for the detonator to be fired. In one application, the controller operates at about 10% (i.e., at a reduced current) of the minimum firing current required to fire the detonator. Other values for this percentage may be used. This makes the process of changing the value of the mode state variable of each switch assembly while the gun string is in reserve safe. Thus, the controller 206 verifies that all switch components: while using reduced current, they are able to communicate and they are able to detect their detonator. In addition, the controller 206 operates at a reduced current to configure the switching assembly to operate in a desired operating mode (e.g., standard mode, fast firing mode, set/fire switching mode, etc.). In one application, as discussed later, the controller 206 can configure all switch assemblies to perform actions in a standard operating mode and configure the bottommost switch assembly as a set/fire switch just prior to running the gun in series into the well. In one embodiment, the controller 206 includes a display that displays all of this information in real time to the well operator and records the results of each test in its non-volatile memory for later analysis and download.

Thus, after the fire command is received in step 422 and the first timer is started in step 424, if no voltage increase above the threshold voltage is detected in step 434 (second condition for firing), the process returns to step 426. If the first timer has counted down the first time interval, then as a safety measure, the process stops the timer in step 428 and returns to wait step 406 because the second condition has not been met.

While the process loops from step 434 back to step 426, etc. during the first time interval, the second timer 246B counts down a second time interval that is much shorter than the first time interval, which results in information regarding the state of the switch assembly being sent to the operator of the gun string in step 432. In this way, the operator is constantly evaluating the state of the switch assembly. Note that this bidirectional exchange of information between the controller 206 and a given switch assembly occurs in the standard mode of operation, rather than for the fast fire mode of operation. For the fast fire mode of operation, commands or data are not exchanged between the surface controller and the switch assembly, which makes this mode "fast" as described below.

However, if the voltage measuring unit V is in step 434 while the first time interval has not elapsed yet_MA voltage increase above the threshold voltage is detected, the process proceeds to step 436 to fire the detonator 230A. Note that unlike all existing methods in the field, the final/final decision regarding firing the detonator is at the switch assembly level (i.e., by the local processor P)_ARather than by surface controller 206). In other words, while the initial decision regarding firing the gun assembly is made by the operator of the gun train at the controller 206, the final decision regarding actually firing the gun assembly is made locally at the switch assembly (in step 434). This two-step decision method ensures that the initial decision is not a mistake and also prevents the detonator from being fired by mistake.

As a further safety measure (fail-safe measure), a third timer (or first timer) is started in step 438 and instructed to count down a third time interval. The third time interval may be greater than the first time interval (e.g., on the order of minutes). In this particular embodiment, the third time interval is approximately 4 minutes. If the detonator is actuated in step 436, as previously described, detonation of the charge in the gun assembly will likely destroy the switch assembly 232A, and thus the process stops here with respect to that particular switch assembly.

However, if the detonator fails to activate for any reason, then the processor P will be activated_AWhen it is determined in step 440 that the third time period has elapsed, it is determined locally in step 442 to shut down the firing process and the process returns to wait step 406. The processor may also send a status report to the controller 206 in step 442 informing that the firing process has failed. Thus, the operator may decide to repeat the firing process or to skip firing of the gun assembly. Regardless of the operator's decision to fire the next gun assembly, the operator again sends a command to the next switch assembly and the process described in fig. 4A-4C is repeated.

However, because of the processor P in the global controller 206 and each switch element_ACommands and/or data exchanged between, so this standard mode of operation of firing the detonator is slow. Most of the steps shown in fig. 4A-4C are avoided if the switching assembly is configured to perform an action according to a fast fire mode of operation, as will be discussed later, and the firing time is reduced.

The process discussed above applies to any of the switch assemblies shown in fig. 3A and 3B. Once the transfer command has been applied to each switch assembly, the controller 206 is able to instruct any switch assembly, regardless of their position in the chain of switch assemblies, to fire its corresponding detonator due to the selectivity afforded by the unique digital address of each switch assembly. This feature is reflected in step 408, where step 408 checks for a match of the numerical address sent by the controller 206 with the numerical address of each switch assembly.

Next, the passage of the detonator to activate the setting tool rather than the detonator of the gun assembly associated with the lower switch assembly is discussedThe process. If a command with the address of lower switch component 232M is sent (see step 408 for verifying the address) and the command is valid (step 412) and the command is neither a change address command (see step 414) nor a pass-through command (see step 418) and the command is neither a fire command (see step 422), then processor P is a processor_AIn step 446 it is determined whether the command is associated with setting the detonator of the tool. If the answer is "no," the process returns to wait step 406. If the answer is "yes," the process proceeds to step 424', which is similar to step 424 discussed above, except that step 424' applies to the setting tool detonator 250 (see FIG. 2) associated with the setting tool 202.

The following steps 426 'to 442' are similar to the corresponding steps 426 to 442, and thus the description thereof is omitted herein. The same safety features (i.e., first through third timers) are implemented for the setting tool as for the gun assembly. Note that it is possible to actuate the detonator of the setting tool only for the lower switch assembly 232M, since this is only the switch assembly that can execute the setting tool commands. This is possible because the lower switch component 232M checks whether the mode state variable in the received command has the first value or the second value. The first value is associated with a fire command and the second value is associated with a set tool command. Thus, when a command from the controller 206 is received and includes the numerical address of the lower switch assembly 232M and the mode state variable has a first value, the processor follows steps 424 through 442. However, if the command includes the numerical address of the lower switch component 232M and the mode state variable has the second value, the processor follows steps 424 'through 442'.

In step 414, the controller 206 sets a setup tool associated with the address. As previously described, each switch assembly has a full or partial address that is pre-assigned or randomly assigned during the manufacturing process of the memory. In step 414, when the controller 206 determines that the switch element 232M is the last switch element in the chain of switch elements, the controller 206 may assign an additional address to the lower switch element 232M. This additional address is directly linked to the setup tool 202 and it is checked in step 446 discussed above.

Returning to the concept of dynamically addressing the switch components (see steps 414 and 416 in FIG. 4A), the following aspects are discussed further for illustration. According to this method, it is possible to set the switch address in the gun string during initial testing, after the gun string has been assembled, or at any other time. The process of dynamic addressing may be accomplished using a test cartridge or control system (e.g., controller 206) designed for this purpose.

In one application, when power is applied to the chain of switch assemblies, the first switch assembly powers up, performs internal testing of its circuitry, and tests for the presence of an initiator. After a short delay it sends this information (see step 402) up to the test box with the uninitialized address. The test cartridge will recognize the address and send a command (see step 414) instructing the switch assembly to reprogram its address to the address sent in the command. The test cartridge then sends a "pass through" command in step 418. At this point, the switch assembly will "pass" the voltage to the next switch assembly in the chain, and the process repeats until all switch assemblies in the chain are considered.

During operation of the gun string, the surface logging and/or perforating system (i.e., the controller 206) may poll the gun string. The polling process is initiated by applying power to the upper switch assembly 232A in the gun string. On power up, the upper switch assembly cable sends its address and the value of the mode state variable up, and then automatically reverts to the low power listening mode state. The controller 206 receives and identifies the unique address of the switch assembly and its mode state variable and locates the switch assembly in the gun string. The controller 206 then sends a digital code (pass-through command) downhole back to the switch assembly that instructs the switch assembly to apply power to the next switch assembly in the string below.

Power is then applied down the gun string to the next switch assembly. This process is repeated for each switch assembly or any number of gun assemblies in the gun string. When the controller 206 detects the lower switch assembly in the string, a record of the number, address and position in the gun string is recorded for all switch assemblies.

As previously mentioned, switch assemblies have been designed with multipurpose operating mode variables. In one application, the switch assembly may be configured to: (1) a standard mode of operation with delivery, a fast mode of operation with delivery, or (2) a set tool mode of operation with delivery, or (4) a ballistic release tool mode of operation, or (5) any combination of these modes. The set tool operating mode may be used to set the tool and associated lower gun assembly. A unique value may be used to determine which mode to use. The set tool mode will follow the same firing procedure discussed above with respect to fig. 4A-4C to set the plug.

After all switch assemblies in the gun string are powered up and all digital addresses are recorded, but the fast fire mode of operation is not detected, all switch assemblies in the gun string are in a "wait for command" low power mode. The operator can then select any switch assembly in the gun string and send a "fire command". Note that the operator does not have to start with the lower gun assembly. In the case of the addressable switch assemblies discussed herein, the operator has the freedom to actuate any switch assembly, wherever located in the chain of switch assemblies. The unique numerical address code for a particular switch assembly in the gun string is immediately transmitted followed by the firing command encoded by the unique number. Once the correctly addressed switching component understands its address code, it checks which mode of operation is to be started and then commands the start of an internal timer (see step 424). Within this timer cycle, the switch assembly cable sends a status/reset code up at 1 second intervals (see step 432), giving the operator a visual indication of the ready to fire status of the switch assembly. The timer cycle is user programmable from 10 to 60 seconds and indicates the time remaining until the switch assembly will abort the firing command and resume normal operation until it is in its previously configured state. Note that the time interval for which the one or more timers are programmed in the switch assembly may be programmed before the switch assembly is lowered into the well, but may also be programmed after they are placed inside the well (see step 414).

An internal voltage measurement circuit of the switching assembly monitors the through line voltage. If the line voltage increases above a threshold voltage (e.g., 140 volts) before the first timer times out, a voltage is applied to the detonator hardwired to the switch assembly by turning on the detonator switch. If the voltage does not increase within the time assigned by the first timer, the firing command is aborted and must be resent from the surface system to begin another timeout window. Once the voltage is above the threshold voltage and the cord has been connected to the detonator, another timer (a third timer, see step 438) is started. In one application, the timer is about 4 minutes and ensures that the detonator is disconnected from the line in case the detonator for any reason does not fire.

However, if the switch assembly has a value for the mode state variable corresponding to the ballistic release tool mode, that particular switch assembly interacts differently than all of the other switch assemblies now discussed. Many operators use a Ballistic Release Tool (BRT) with the gun string, and a BRT is a tool that can use an addressable switch assembly to initiate a ballistic reaction to separate the gun string from its cable or other tool used to lower the gun string into the well. The BRT is useful in the event that the gun string becomes stuck in the hole at some point below the BRT, as the operator has the option to separate the cable from the gun string at the location of the BRT, and is then able to retrieve the cable and bring it back to the surface without the gun string. The gun string can later be recovered using a method that can be pulled harder than the cable can be pulled. A risk of using an addressable switch assembly configured to perform an action in a standard operating mode in a BRT mode is that when a user intends to fire one of the top gun assemblies in the gun string, it creates a relatively high probability that the user inadvertently releases the gun string.

Thus, the switch element may be programmed with a specific address or a specific value for the mode state variable that places the switch element in the BRT mode. When a switch assembly is in the BRT mode, it behaves differently from other switch assemblies. On power up, the switch component in the BRT mode does not send its address in step 402, as discussed above with respect to fig. 4A, but instead listens for commands to be specifically sent from the controller 206 to its address (i.e., the switch component configured in the BRT mode of operation does not "say, unless so stated"). In the event that the operator wishes to release the gun string, they may send a "release" command to the specific BRT switch assembly address, and this will initiate a release sequence, which may be the same as the firing sequence described in steps 424 to 442 or 424 'to 442' discussed above in relation to fig. 4A to 4C, with the exception that: it can only be activated by sending a "BRT release" command on the "BRT activated switch assembly. While most switches will effect their transfer upon receipt of a "transfer" command as discussed above with respect to step 418, the BRT switch component will monitor the line voltage and effect its transfer at times when the line voltage exceeds a minimum threshold (e.g., 35V). This enables an operator to power up the wires to a lower voltage (e.g., 30V) and communicate with the BRT switch assembly without the BRT switch assembly enabling its feed-through and powering up the lower switch assembly. For this mode, step 402 may therefore be modified to check the value of the mode state variable at that time, and if the value is consistent with the value associated with the BRT mode of operation, then that particular switch assembly does not send its numerical address up.

The previous embodiments discuss how various commands are sent from the controller 206 to the switch assemblies and how the switch assemblies send various information (e.g., their digital addresses or their status) to the controller. Thus, bi-directional communication is established between the controller and the switch assembly for the standard mode of operation. However, such two-way communication takes time and limits the possibility of quickly firing the shaped charges of the various gun assemblies of the gun string. Thus, as discussed next, it is possible to implement different schemes for firing the gun assembly without requiring data exchange between the surface controller 206 and the multiple switch assemblies, and this is a fast firing mode of operation.

According to this embodiment, as shown in fig. 6, the switching assembly 232 may be modified to support the fast-fire mode of operation by including a power supply 260, the power supply 260 being configured to provide various voltages to the switching assembly independent of the controller 206. For example, power supply 260 may include one or more transistors, diodes, resistors, and capacitors. In one application, the power supply 260 is connected to a telemetry system 205 including leads 204 and 208 and communicates with the controller 206. The telemetry system 205 is conveyed by a cable 222 from the surface into the well to each switch assembly, as shown in FIG. 7. The power supply 260 may also generate various DC voltages (e.g., 12V and 5V for the internal nodes of the switching component 632). Note that the configuration of the switch assembly shown in fig. 6 is described in international patent application PCT/US2019/036538, assigned to the assignee of the present application, which is incorporated herein by reference in its entirety. However, the switch assembly in the PCT application is not configured to enter a different mode of operation than the fast fire mode of operation (i.e., it is not configured as a switchable switch assembly).

Schematically shown in FIG. 6 but with a processor P similar to that of FIG. 3A_AProcessors P of the same structure_AConnected to a transmit module 270 and a receive module 272, both of which are added to the switch assembly 232. The transmitting module 270 and the receiving module 272 may be considered transceivers. Through these transmission elements, the previously addressable switch assembly 232 becomes switchable and the addressable switch assembly 632, as now discussed. Note that the switchable and addressable switch assembly 632 may still perform all functions and have all the capabilities of the addressable switch assembly 232. However, with the addition of a power source and transceiver, the switchable and addressable switch assembly 632 may now also perform the fast fire mode of operation or any of the modes previously discussed. Each of these receive and transmitter modules is implemented in hardware and may include, for example, transistors and resistors. Note that a common transmit or receive module or switch assembly or processor is indicated in fig. 6 by a corresponding reference numeral (e.g., 632), while the same element, when present in a chain of switch assemblies, is indicated by a corresponding reference numeral (e.g., 632A) followed by a letter specific to each switch assembly in the chain.

The function of the switchable and addressable switch assembly 632 (referred to herein simply as the "switch assembly") shown in fig. 6 will now be discussed with respect to fig. 7. The switch assembly 632 may also be used in a standard mode of operation because the entire structure of the switch assembly 232 resides in the switch assembly 632. The additional structure shown in fig. 6 with respect to the switch assembly enables a fast excitation switching mode. This means that the switch assembly 632 can be used in either mode by simply changing the value of its mode state variable. Thus, if the switch assembly 632 is used by an operator of a well, any of the modes discussed herein can be implemented by using the same switch assembly configuration. This is not possible with the existing switch assemblies.

For simplicity, fig. 7 shows a gun string 700 that includes only three switch assemblies. However, the gun string may have any number of switch assemblies. Also for simplicity, each switch assembly is shown as a box with two switches, a microprocessor, a transmit module, and a receive module. Switch assembly 632A is considered closest to the top of the well and switch assembly 632C is considered closest to the toe of the well. This means that switch assembly 632A can also be programmed to use the BRT mode of operation, while switch assembly 632C can be programmed to use the set/fire mode of operation. For the other switch assemblies 632, the BRT and set/fire modes of operation are not required, but may be implemented if so desired by the well operator. Charges and other physical elements attached to or making up the gun assembly are omitted herein for simplicity. The figure shows only three switch assemblies and their electrical connections to other switches, to the controller from the surface and to their detonators.

When the switch assemblies 632 are processed by the controller 206 to perform actions in the fast fire mode of operation, each switch assembly acts as a hybrid switch assembly (i.e., it need not have a digital address and commands need not be received from a surface to fire the hybrid switch assembly). If the switch assembly 632 is programmed to operate in the fast fire mode of operation, the switch assembly will pass through various state machines. In one implementation, each switch assembly passes through 6 state machines, as now discussed. Those skilled in the art will appreciate that the switch assembly may pass through more or fewer state machines depending on the value of the associated mode state variable.

After the string of switching elements is powered up with the selected voltage, similar to the embodiment shown in fig. 4A-4C, and the processor of the switching elements determines in step 500 that the value of the mode state variable corresponds to the fast fire mode of operation, the method proceeds to step 520, which is now detailed. In this mode of operation, the selected voltage (referred to herein as the supply voltage) may be a negative voltage between 20V and 90V, which is applied between leads 204 and 208 in fig. 7. Other voltages may be used. Once the chain of switch assemblies is powered up, each switch assembly determines whether it is capable of firing the corresponding detonator. The switch assembly then communicates locally with an adjacent switch assembly (typically located deeper downhole) to determine if there is a switch below it that can also be activated. Note that in the fast fire mode of operation, communication of the switch assembly is primarily directed to neighboring switch assemblies, not to controller 206. This saves time because most of the commands required for a standard communication protocol between the switch assembly and the surface controller 206 are eliminated. For this reason, the operation mode is a fast excitation mode.

As each switching assembly makes this determination, it will send a pair of voltage pulses to surface controller 206. Surface controller 206 may interpret these pulses to determine how many switching elements are online, knowing that bottom switching element 632C will fire when the line voltage increases above the firing voltage. In this implementation, the excitation voltage is greater than 140V. The surface controller then increases the line voltage to greater than the firing voltage, and the bottom switch assembly, upon detecting this voltage increase, fires its associated detonator within a specified time window.

After the switch assembly is fired, power to the chain of switch assemblies is interrupted and then reapplied to the entire chain so that the configuration process described in the previous step is repeated after each firing to again determine which is the current bottom switch assembly. If a downhole wiring problem or electronic fault prevents the switching assembly from being able to fire, the switching assembly above it will automatically become the last switching assembly in the string without interference from the controller 206. This means that the process is independent of any instructions from the surface controller 206 (i.e. no commands from the surface controller are required), which speeds up the firing process and makes the fast firing mode of operation indeed fast. Note, however, that if the switch assembly is reprogrammed to be in a standard mode of operation or other mode of operation, the switch assembly 632 is able to exchange information bi-directionally with the controller 206.

The six states that each switch assembly passes through will now be discussed. The first state entered by the switch assembly is the POWER-UP state. The inventory process related to the power-up state of the chain of switch assemblies occurs at a rate of about 5 switches/second with a slight delay on the first switch assembly while waiting for the cable voltage to stabilize at power-up. The firmware of the switch assembly implements the state machine as follows. On each power up, the movable switch assembly with the detonator present will take approximately 200 milliseconds to travel through the state machine. The switch assembly will first check if it has been previously activated (i.e., if there is an inactive flag set). If the flag is set, the switch assembly will go to sleep. Otherwise, the switch assembly will read the input V of the A/D converter_INThe scan head voltage (i.e., the voltage between lines 204 and 208 in fig. 6) is started, and no further action is taken unless the following two conditions are met:

(1) the line voltage is stable at a value less than 90V (e.g., the line voltage has not changed by more than 5V) for the last T1 seconds (e.g., T1 ═ 16 ms); and

(2) the switch assembly has been powered up for at least T2 seconds (e.g., T2 ═ 20 ms).

By requiring that both conditions are met, the switching assembly cannot enter the firing state as a result of the firing voltage being applied either intentionally or immediately due to a line "under-voltage" after firing the previous switching assembly. The above-described head voltage readings will be referenced later to determine if the feed-through lines are shorted. Once the required conditions are met, the switch assembly will check for the presence of the detonator. Note that all future timing of the switching components is based on the time at which the switching components exit this state (i.e., the pulse generated by the switch 200 milliseconds after the power-on action is actually referenced as 180 milliseconds after leaving this state).

After power up, each switch assembly in the string will end up in one of 3 possible states:

it will determine that it cannot fire due to no detonator or having been previously set to "inert" and will go to sleep; or

It will determine that it can fire and that there is another detonator equipped switch assembly below it, in which case it will be able to power the lower switch assembly and then go to sleep; or

It will determine that it is capable of firing and that there is no detonator equipped switching assembly below it, in which case it will remove firing on the detonator if the line voltage is sensed to be greater than the firing voltage (e.g. 140V) within a given time window (e.g. 45 second window).

Note that these states are configured to operate each switch assembly independently of the controller 206 (i.e., without requiring instructions from the controller 206).

The second state of the switching element is the DETONATOR CHECK state. Once the line voltage of the switching assembly has stabilized, it will check whether it senses the detonator. The presence of the detonator essentially means that there is a connected 50 ohm resistor between the cable armor wires 208 (see fig. 6) and the wires 212A (see fig. 6) connecting the detonator switch 236A to the detonator 230A. The determination is made by the processor P_ABy sensing the appropriate voltage for the detonator. If the voltage sensed on the detonator cord is greater than 20V, the processor P of the switch assembly 232A_AThe presence of the detonator 230A is determined. If the detonator is not detected, the microcontroller instructs the switch assembly to go to sleep and will not attempt to communicate with the surface controller or any other switch assembly. If the microcontroller detects the detonator, the microcontroller of the switch assembly will place a short (-24 μ s) pulse on the line (204A-i) to alert the next (upper) switch assembly to the presence of the lower switch assembly with the detonator. The switch assembly will then do nothing for 75ms, after which it will check its feedthrough connections 204A-o.

The third state of the switch assembly is a feedtrhroouh or through line inspection state. The feedthrough check will determine whether the feedthrough lines 204A-o are shorted. If the feed-through lines are shorted, there will be a near V present on lines 204A-o_INThe voltage of (c). Measuring the voltage on the line, andif it is at voltage V_INWithin 5V, the microcontroller of the switching assembly determines that the feedthrough is shorted. If the feedthrough line is shorted, the microcontroller of the switching assembly determines that it must be the final switching assembly in the string, and therefore it enters the PRE-FIRE state. If the feedthrough wires are not shorted, the microcontroller of the switch assembly will enable its bypass wire (i.e., turn on the through wire switch 234A) and prepare to listen for a 24 μ S pulse indicating that the underlying switch assembly has an initiator. The terms "below" and "above" are used herein to mean "downstream" and "upstream" relative to a well.

The fourth state of the switch assembly is the LISTEN state for the lower switch assembly. As described above, the switching assembly will do nothing after power application until it has been powered up for at least 20ms and its head voltage is stable. The "listen" state is entered directly after the feed-through line has been enabled, and the first thing the microcontroller will do during the "listen" state is wait 15ms, and can then trigger an interrupt if a pulse from the lower switch component is detected. The microcontroller will then wait another 15 milliseconds, turn off the bypass to the lower switch component (i.e., switch 234A), and then check whether an interrupt is generated inside the listening window. If no interrupt is generated, the switching assembly determines that there is no detonator equipped switching assembly below it and therefore it will enter the PRE-FIRE state. If an interrupt is generated, this will be interpreted as the presence of the lower switch assembly with the detonator and the microcontroller will enter the INLINE state.

The fifth state of the switch assembly is the INLINE state. If the switch assembly is in this state, it has determined that it has a detonator and there is a switch assembly below it that also has a detonator. The microcontroller will inform the surface controller that it is an inline switch assembly by sending two long pulses P1 and P2 at times T3 and T4 (e.g., after power up, T3 is 180ms and T4 is 200 ms). Immediately after this operation, the microcontroller will enable the bypass line (pass-through switch 234A) for the next switch component to start its inventory process, and then go to sleep to minimize current consumption.

The sixth state of the switching assembly is the PRE-FIRE state. If the switch assembly reaches this state, it has determined that it has an initiator, but there is no initiator-equipped switch assembly below it. The microcontroller will notify the surface controller via the transmit module 270 that it is a terminating switch assembly. The microcontroller will send two long pulses P3 and P4 at times T5 and T6 (e.g., T5 ═ 190ms and T6 ═ 200ms) and then prepare to unload the fire on the detonator when it detects that the line voltage is higher than the firing voltage (e.g., 140V). Immediately after sending these two pulses, the switching assembly will start a timer (e.g., a 45 second timer) for measuring the time window, and then verify again that its head voltage is below 90V and stable for at least 20 ms. Once this has been confirmed, it will begin reading its head voltage to determine if there is a voltage greater than the firing voltage (e.g., 140V). If a voltage greater than the fire voltage is detected, the microcontroller will mark itself as inert to any future power-up and then enable fire line 212A. If the 45 second timer expires before the firing voltage is sensed, the switching assembly will go to sleep and a power cycle will be required to reconfigure the switching assembly string.

An alternative state is the SETTING TOOL CHECK state. Alternatively, one of the previous states may be modified to include the functionality discussed herein. Once the line voltage of the switching assembly has stabilized, it will check if it senses a setting tool. In one application, the switch assembly will also check for the presence of a detonator that is not associated with the setting tool. The determination is made by the processor P_ABy sensing the appropriate voltage for setting the tool. If the processor P of the switch component 632C_ADetermining that the setup tool 202 is present, the switch assembly sends two pulses to the surface controller to inform of the determination. Further, switch assembly 632C will place a short (-24 μ s) pulse on line (204C-i) to alert the next (upper) switch assembly to the presence of the lower switch assembly with the setting tool and/or detonator. As mentioned before, these two pulses can be separated for up to 15 ms. If the setting tool is not detected and the detonator is not detected, the microcontroller instructs the switch assembly to go to sleep and no attempt will be made to control the surfaceOr any other switching component. If the setting tool is not detected and only the detonator is detected, the microcontroller of the switch assembly will place a short (-24 mus) pulse on the wire (204A-i) to alert the next (upper) switch assembly to the presence of the lower switch assembly with the detonator. The switch assembly will then do nothing for 75ms, after which it will check its feedthrough connections 204A-o.

Those skilled in the art will appreciate that the times and voltages used to describe the above 6(7) states are exemplary and that other values may be used. Furthermore, those skilled in the art will appreciate the simplicity of the communication scheme used by the microcontroller to communicate with the surface controller or with other microcontrollers from the chain. Here, the examples discussed above only use pulses with different degrees of time separation for communication. Therefore, the digital address of the microcontroller is not necessary to perform this type of communication.

A method for switching the switch assembly 632 from one operating mode to another operating mode will now be discussed with respect to fig. 8. The method begins in step 800 when the operator connects the surface controller 206 to a portion or the entire gun string and sends a command to the switch assembly 632 that needs to be switched in step 802. Note that all of the switch assemblies 632 in the gun string 200 or 700 share the structure shown in FIG. 6 (i.e., each switch assembly is configured to communicate directly with the surface controller or directly with additional switch assemblies). The command includes information for changing the value of the mode state variable stored by each switch assembly in its memory 238. For example, if the default value of the mode state variable is zero (which corresponds to a standard operating mode), the command sent by surface controller 206 includes an instruction such that switch assembly 632 changes the variable from zero to 1 in step 804, where 1 is associated with a fast fire operating mode. More than one number may be used if the mode state variable requires more values, e.g., to also implement a set/fire mode of operation or a fast fire set/fire mode of operation, etc. (i.e., 00 for a standard mode of operation, 11 for a fast fire mode of operation, 01 for a set/fire mode of operation, 10 for a fast fire set/fire mode of operation, etc.). Those skilled in the art will appreciate that any number of values may be implemented for the mode state variables using the numbers 0 and 1 or in any other known manner.

In step 806, the processor of the switch assembly erases the previous values of the mode state variables from the non-volatile memory and stores the new values received from the surface controller 206. In one embodiment, the steps of transmitting, changing and storing are repeated for each switch assembly in the gun string. However, in another embodiment, the steps of sending, changing and storing are performed only for the first switch assembly of the gun string.

Setting the value of each mode state variable by the well operator may be performed at the surface when all switch assemblies are on the surface, or after the entire gun string has been assembled and lowered into the well. In other words, telemetry for controlling the switch assembly shown in fig. 6 allows the switch assembly to be switched from one operating mode to another regardless of the position of the switch assembly. Note that this operation may be performed when the controller is connected to a single switch assembly, some switch assemblies, or all switch assemblies of the gun string 700. In one application, when all of the switch assemblies 632 are connected to the controller 206, it is possible to change one, a subset, or all of the switch assemblies of the gun string from one value to another. In yet another embodiment, it is possible to change the switching element from a first value to a second value different from the first value, change another switching element in the gun string from the first value to a third value different from the first and second values, and so on. In other words, the controller can selectively change the values of the mode state variables of one or more switching assemblies to various desired values, either sequentially or during the same operation. Any one or combination of the steps and processes discussed with respect to fig. 8 may be performed at the manufacturing facility of the switch assembly, in which case the surface controller 206 is a computer system belonging to an operator of the facility, and the telemetry system 205 includes any wiring connecting the controller to the switch assembly. The same as shown in fig. 8 may be performed for only the switch assembly while each switch assembly is connected to the controller, or when all or some of the switch assemblies are connected to the controller togetherThe method is associated with the steps. If the switch assembly 632 is directly connected to a controller in the manufacturing plant, the telemetry system 205 refers to the wiring used to connect the controller to the switch assembly, the interface I/O shown in FIG. 3A may be used as a port to communicate with the controller, and the processor P_AThe various steps discussed in the method illustrated in fig. 8 are being performed with or without a controller. In other words, all steps discussed with respect to the method may be performed by the manufacturer of the switch assembly in a factory located several hundred kilometers from the well, or by the operator of the well while the switch assembly is on the surface, beside the well, or already deployed in the well. This means that in one application, an existing addressable switch assembly may be modified in firmware to perform the steps discussed herein and transition from one mode of operation to another.

In one application, the sending, changing and storing steps discussed above with respect to fig. 8 are only performed for one switch assembly of the gun string, and that switch assembly is the first in the chain of switch assemblies. In this or another application, each of the first and second operating modes is one of a standard operating mode, a fast fire operating mode, a set/fire operating mode, a fast set/fire operating mode, and a ballistic release tool operating mode. The operator may also define other modes according to the needs of each well.

The standard mode of operation uses two-way data communication between the surface controller and the switch assembly. The fast active mode of operation does not use data communication (only sending one or more currents or voltages having different values along the telemetry system; data communication is understood herein to include commands identifying the digital address of the switch assembly and additional information instructing a particular switch assembly associated with the digital address to perform a particular function) between the surface controller and the switch assembly for activating the switch assembly, such that the fast active mode of operation takes less time than the standard mode of operation. The set/fire mode is used when the switch assembly is connected between the gun assembly and the setting tool, and the ballistic release tool mode is used on the first switch assembly in the gun string to release the gun string inside the well.

After the switching assembly of the gun string has been configured (switched) to operate in the desired mode of operation, the gun string may now be ready for operation. Note that by using the same structure for all switch assemblies regardless of the mode of operation, and having the ability to set each switch assembly to a desired mode of operation that may be different from the original use of the switch assembly, the operator need not predict what type of switch assembly to use for a given well, and avoid the need to have to use different switch assemblies if the conditions at the well have changed, which is not only time consuming, but also expensive and prone to error.

Having assembled the gun string in the well, the operator is now ready to fire the shaped charges of the multiple gun assemblies of the gun string 700. In the embodiment shown in FIG. 9, the operator begins in step 900 by powering up the gun string (i.e., sending a small current (much less than the firing current) from the controller 206 to the switch assembly 632). Local processor P for each switch assembly_AThe value of the mode state variable may be checked in step 902 at this early point in the process. If the value is associated with the standard mode of operation, the method continues to step 402 in FIG. 4A and follows the remaining steps shown therein and discussed above.

However, if it is determined in step 902 that the value is associated with the fast fire mode of operation discussed above with respect to FIG. 7, then the method continues in step 906 with the fast fire mode of operation and activates the switch assemblies by using, in this embodiment, only changes in the voltage applied to the gun string rather than commands specifically addressed to each switch assembly. In other words, for the fast fire mode of operation, the digital address of the switch assembly is not used to instruct the switch assembly to fire the detonator. Those skilled in the art will appreciate that the switch assembly may be activated in other ways as long as no command is sent from the controller 206.

It is also possible to determine in step 902 that the value of the mode state variable is associated with a BRT mode of operation or a set/fire mode of operation, in which case the method continues in that mode in step 908. Both BRT and set/fire modes of operation have been described above. In this manner, the method illustrated in FIG. 9 is able to select which operating mode to implement for the switch assembly of the gun string 700 based on the value of the mode state variable.

In one application, the plurality of operating modes includes a standard operating mode and a fast fire operating mode, wherein the fast fire operating mode fires the switch assembly in less time than the standard mode. In another application, the plurality of operating modes include two or more of a standard operating mode, a fast fire operating mode, a set/fire operating mode, and a ballistic release tool operating mode. In this application, the standard mode of operation uses bidirectional data communication between the surface controller and the switch assembly, the fast fire mode of operation does not use data communication between the surface controller and the switch assembly to fire the switch assembly such that the fast fire mode of operation takes less time than the standard mode of operation, the set/fire mode of operation is used when the switch assembly is connected between the gun string assembly and the setting tool, and the ballistic release tool mode of operation is used on the first switch assembly in the gun string to release the gun string inside the well. In one application, the steps of inspecting and activating are performed while the switch assembly is in the well. It is also possible that the steps of checking and activating are only performed for a single switch assembly of the gun string, and the switch assembly is the first in the chain of switch assemblies.

The disclosed embodiments provide methods and systems for selectively actuating one or more gun assemblies in a gun string according to a desired operating mode stored at a switch assembly. It should be understood that this description is not intended to limit the invention. On the contrary, the exemplary embodiments are intended to cover alternatives, modifications and equivalents, which may be included within the spirit and scope of the invention as defined by the appended claims. Furthermore, in the detailed description of the exemplary embodiments, numerous specific details are set forth in order to provide a thorough understanding of the claimed invention. However, it will be understood by those skilled in the art that various embodiments may be practiced without these specific details.

Although the features and elements of the present exemplary embodiments are described in the embodiments in particular combinations, each feature or element can be used alone without the other features and elements of the embodiments or in various combinations with or without other features and elements disclosed herein.

This written description uses examples of the subject matter disclosed to enable any person skilled in the art to practice the same subject matter, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the subject matter is defined by the claims, and may include other examples that occur to those skilled in the art. These other examples are intended to fall within the scope of the claims.

Claims (20)

1. A switchable and addressable switch assembly (632) that is part of a chain of switch assemblies (632A-632C) in a gun string (700), the switch assembly (632) comprising:

an interface (I/O) configured to connect (800) to a controller (206) along a telemetry system (205); and

processor (P)_A) Connected to the interface (I/O) and configured to:

receiving (802) a command from the controller (206) along the telemetry system (205) to change a first value of a mode state variable to a desired second value, wherein the first value is associated with a first operating mode of the switch assembly (632) and the second mode is associated with a second operating mode different from the first operating mode;

changing (804) the first value to the second value; and

storing (806) the second value of the mode state variable in a non-volatile memory (238).

2. The switch assembly of claim 1, wherein said changing and said storing are performed while said switch assembly is at a surface.

3. The switch assembly of claim 1, wherein said changing and said storing are performed while said switch assembly is in a well.

4. The switch assembly of claim 1, wherein the sending, the changing, and the storing are repeated for each switch assembly in the gun string.

5. The switch assembly of claim 1, wherein said transmitting, said changing, and said storing are performed only for said switch assembly of said gun string, and said switch assembly is the first of said chain of switch assemblies.

6. The switch assembly of claim 1, wherein each of the first and second operating modes is one of a standard operating mode, a fast fire operating mode, a set/fire operating mode, and a ballistic release tool operating mode.

7. The switch assembly of claim 6, wherein the standard mode of operation uses two-way data communication between a surface controller at the well and the switch assembly.

8. The switch assembly of claim 7, wherein the fast fire mode of operation does not use data communication between the surface controller and the switch assembly to fire the switch assembly, such that the fast fire mode of operation takes less time than the standard mode of operation.

9. The switch assembly of claim 8, wherein the set/fire mode of operation is used when the switch assembly is connected between a gun assembly and a setting tool.

10. The switch assembly of claim 9, wherein the ballistic release tool operating mode is used when the switch assembly is the first switch assembly in the gun string, thereby releasing the gun string inside the well.

11. A method for energizing a switch assembly (632) that is part of a gun string (700), the method comprising:

receiving power (900) at the switch assembly (632) from a surface controller (206);

checking (902), at the switch assembly (632), a value of a mode state variable stored in a non-volatile memory (238); and

activating (904, 906, 908) the switch assembly (632) according to one of a plurality of operating modes based on the value of the mode state variable,

wherein each of the plurality of operating modes is different from the other operating modes of the plurality of operating modes.

12. The method of claim 11, wherein the plurality of operating modes includes a standard operating mode and a fast fire operating mode, wherein the fast fire operating mode fires the switch assembly in less time than the standard operating mode.

13. The method of claim 11, wherein the plurality of operating modes include two or more of a standard operating mode, a fast fire operating mode, a set/fire operating mode, and a ballistic release tool operating mode.

14. The method of claim 13, wherein the standard mode of operation uses two-way data communication between the surface controller and the switch assembly.

15. The method of claim 14, wherein the fast fire mode of operation does not use data communication between the surface controller and the switch assembly to fire the switch assembly, such that the fast fire mode of operation takes less time than the standard mode of operation.

16. The method of claim 15, wherein the set/fire mode of operation is used when the switch assembly is connected between a gun assembly and a setting tool.

17. The method of claim 16, wherein the ballistic release tool operating mode is used on a first switch assembly in the gun string to release the gun string inside the well.

18. The method of claim 11, wherein the steps of inspecting and activating are performed while the switch assembly is in the well.

19. The method of claim 11, wherein the steps of checking and activating are performed only for the switch assembly of the gun string, and the switch assembly is the first in the chain of switch assemblies.

20. A switchable and addressable switch assembly (632) configured to be connected to a gun assembly in a gun string (700) for energizing the gun assembly, the switch assembly (632) comprising:

processor (P)_A) Configured to check a value of a mode state variable;

a memory (238) configured to store (1) the value of the mode state variable and to store (2) a unique digital address that makes the switch assembly addressable;

a pass-through switch (234) configured to allow a signal from the surface controller (204) to pass to a next switch component;

an initiator switch (236) configured to complete a circuit to an initiator (230) to initiate the initiator (230); and

a transceiver (270, 272) configured to communicate directly with the next switching component,

wherein the value of the mode state variable is associated with a plurality of operating modes, and

wherein the switch assembly is switched from one operating mode to another operating mode by changing the value of the mode state variable.

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